In a small, fragile last-minute victory for common sense, Congress is moving to delay some of the Pentagon’s plans to shift thousands of jobs around the Washington region — plans that will surely make traffic worse.

Hard to imagine, but worse is actually possible. In fact, it’s practically guaranteed.

That’s because the new proposal, although welcome, is six years late and won’t correct the long-term problem.

As a result, thousands of additional cars are eventually going to be channeled onto routes plagued by bumper-to-bumper traffic in Northern Virginia and suburban Maryland. Avoiding that would require major road and transit improvements on a vastly bigger and costlier scale than anyone envisions.

The proposed postponement is “just buying time until we get to shutdown in the area. I’m all for it, because it’s delaying the inevitable pain. But it’s not solving the issue,” said Jeff McKay (D), a member of the Fairfax County Board of Supervisors whose constituents in the Lee District will be especially affected by the job moves.

The potential temporary respite takes the form of a House bill that would allow the Defense Department to pick seven military bases in the nation where it could wait up to a year to transfer workers, instead of sticking to the deadline of Sept. 15.

The changes were originally adopted in 2005 under the Base Realignment and Closure Commission, or BRAC.

Assuming the Senate approves the House bill, the Pentagon is expected at least to delay the move of 6,400 workers to the new Mark Center in Alexandria. That’s the single-most gridlock-inducing change anticipated in our area. It will force many commuters who ride Metro to jobs in Crystal City to start driving to work on Interstate 395, one of the area’s main bottlenecks.

The Pentagon might also agree to delay shifting thousands of workers to Fort Belvoir in southern Fairfax. The change there is going to aggravate congestion along Route 1.

The delays would help modestly by giving the federal and state governments more time to add ramps, upgrade intersections and make other improvements to help handle the increased congestion. For the Mark Center, the bill would cap the number of new parking spaces until some of those improvements are completed.

In suburban Maryland, it seems unlikely that there’d be any change in the schedule.

Bethesda, in particular, is concerned about a sharp increase in traffic on Wisconsin Avenue when the Walter Reed Army Medical Center moves there from the District. The local community was hoping that the Medical Center Metro station on the Red Line would bear the brunt of the change, but necessary improvements are overdue.

“I always saw it as an opportunity to draw attention to the area and make it a transit-oriented development showcase. Unfortunately, in my opinion, that sort of planning, vision, enthusiasm and resources never came together,” said Ilaya Hopkins, East Bethesda’s representative on the Montgomery County BRAC Implementation Committee.

For the sake of Northern Virginia, it’s obviously imperative that the Senate approve the measure allowing for delays and that the Pentagon take full advantage of them. Still, the whole issue highlights once again our region’s dependence on the federal government and a lack of effective coordination that’s self-defeating for both parties.

The IG report, released in April, said the Pentagon’s original study “may not be sufficient” to justify its finding that the change wouldn’t have any significant impact on traffic. It faulted the Pentagon for failing to look at traffic consequences beyond this year and for underestimating the impact on I-395.

That report, along with an equally critical one from the National Academy of Sciences in February, helped persuade Republicans in the House to support the plan to offer delays. It’s still a long way from a solution, though.

“These measures would take a situation that’s going to be awful and make it manageable but still difficult,” Rep. Jim Moran (D-Va.), who has played a leading role in promoting the House bill, said of the Mark Center.

But he said that “we can’t undo the main problem, which was the Army’s decision” to make the change in the first place.

No column Sunday. My next one will be June 9. However, I will discuss local issues as usual at 8:51 a.m. Friday on WAMU (88.5 FM).